You can help this along some by locking up hens with chicks. I usually keep them locked up until 4 months when I switch them off chick starter (or earlier if I need the baby pen for a newer clutch), but any amount of time is helpful. Not required obviously, but mine are by the house and finding dead chicks is just ehhh when I could avoid it.Just this morning a hen I didn’t know was setting came out of hiding with a new clutch of bitties. Some clutches will have a near 100% survival rate, others will have a near 100% loss rate, depending on lots of factors. Once you get a breeding population established of a survival oriented breed, you sit back and let them do the rest.